Pulp treating process and the product



Patented Apr. 25, 1933 MAURAN I. PARSONS, OF MILLINOCKET, MAINE PULP TREATING PROCESS AND THE PRODUCT No Drawing.

This invention relates in general to the method of producing from vegetable fibers a lumber-like product having substantial insulating value and the resulting product.

One of the objects of this invention is the provision of a new and novel process for the treatment of vegetable fibers to prepare them for use in making composition fiber board.

A further object of this invention is the provision of a novel combination of steps for treating vegetable fibers and compacting them into suitable forms to provide a lumber-like product having high insulating value and analogous products.

A still further object of this invention is the treatment of vegetable fibers for disintegration into fiber bundles and to somewhat split and fray out these fiber bundles without destroying the natural characteristics of the fiber bundles or reducing the material to individual fibers.

A still further object of this invention is to provide a product composed of fibers produced by the above process. I

The purpose of this invention is to provide a suitable process for the treatment of vegetable fibers such as marsh or low-land grasses, up-land grasses and cereal straws such as rye, wheat, oats, barley and rice and other vegetable fibers.

It has been usual heretofore in the treatment of various natural fibers for preparing paper pulp and the like, to carry on the di- 5 gesting process until the fibers have become disintegrated into a shapeless mass or pulp, a breaking down to individual fibers, at times going even further and more or less breaking down individual fibers. This resuit has been produced by using strong, di-

gesting solution and digesting the fibers for a considerable period of time.

It has been found that the quality of the product produced, depends upon retaining the natural characteristics of the fibers, that 1s, as to form, tensile strength, resilience and the like and the method of this invention has been provided in order that these natural characteristics of the fibers may be pre:

served,

Application. filed July 5, 1928. Serial No. 290,717.

The following process has been found to be particularly adaptable to the treatment of wheat straw. The raw material is treated in its original form or broken up into suitable lengths by cutting, etc. and is then digested by cooking in a solution of an alkali of the alkali metal group, such as caustic soda or alkalis of the alkaline earth group such as lime of'alkalis of the heavy metal group, aluminium hydroxide, for example, or salts of these metal groups such as chloride, nitrates, sulphites, carbonates and sulphides.

Concentration of the digestingv solution should be such that the natural fibers are not broken down into a pulp mass but rather broken up into fibre bundles which maintain their original and natural characteristics. The digesting solution may vary from a low value such as one percent to as high as ten percent concentration or at a rate of from one percent to five percent chemical to the bonedry weight of the material being treated. The digesting step is carried on for such a length of time and under such a pressure as to release the fiber bundles without release of nor attack of the individual fibers to de stroy their natural characteristics. The length of time of treatment and the pressure will vary considerably, depending upon the condition of the raw material concentration of the digesting solution and it is not therefore necessary to particularly disclose the length of time of treatment since they vary over wide ranges but a digestion with a two percent caustic concentration for two hours at thirty-five pounds pressure is representative. While this treatment may produce some individual fibers, it has beenfound that in the main the fibre bundles maintain their natural form and characteristics. The digested fiber bundles are then washed to free them of the digesting solution and are treated in various well known manners such as by means of rotary suction filters or by suction to remove the moisture therefrom. 95

Comparatively dried fibers are then sized with suitable chemicals such as a mixture of alum and rosin. The fiber can also be sized while in water suspension but the relatively y condition is th t preferred. The mixture is then passed through a beating engine to somewhat break down the fiber bundles, to somewhat split) them up and fray them out, but not to break them down or reduce them to their individual fiber components. These bers with the addition of a fiber which is preferably hydrated paper pulp are then used to prepare the finished product in any suitable form and of any suitable dimensions such as in the form of boards by molding or weaving. A rotary mold roll may be utilized or the material may be mixed with water and flowed into a modified Fourdrinier machine adapted for the purpose so as to form sheets of suitable thickness or the fibers may be com resed b means of a pres to form the finished pr act. The pressure used may vary over wide ranges depending upon the density and tensile strength which the finished product is to have.

It' will be seen from the foregoing disclosure that I have disclosed a novel process for the treatment of all forms of vegetable fibers and "articular wheat straw. It will be apparent t at many changes in the details of procedure and relative, arrangement of steps will readily occur to those skilled in the art, for instance, instead of making a product straw by subjection to mild hydrolysis at a 7 pressure and for a time sufiicient to soften but not to remove the binding and encrusting substances thereof, refining to partially break down the fiber bundles of digested wheat straw, the addition of not more than 45% of pulped hydratable paper making fiber, the brous material sized, formed from a water suspension into board form and the water content subsequently substantially evaporated therefrom.

In testimony whereof I have hereunto set my hand on this'29th day of June A. D., 1928.

- MAURAN F. PARSONS.

completely of one material such as wheat I straw, and

a product may be made of wheat straw mixtures of other vegetable fibers in proportions.

I do not therefore desire to be limited to the particular procedure outlined by me for purposes of my illustration but rather to the int and scope of the invention as it is deed below.

What I seek to secure by United States Letters Patent is:

1. A fiber'composition board comprising a compressed mass of sized wheat straw fibers and a wood pulp filter, the wheat straw fiber bundles being but slightly disintegrated and of various lengths.

2. A fiber composition board composed of a mam of varied length sized cereal straw fibers and bagasse and a filler of wood pulp for binding the fiber together.

3. A composition fiber board comprising an intimate mixture of cereal straw fibers and a binding mixture of wood pulp paper making fibers, said cereal straw fibers sized and Partially disrupted but having their natura form and characteristics.

4. The method of obtaining from vegetable fiber a lumber like product having insulation properties which comprises disintegrating wheat straw into suitable lengths, then digesting the same in a low percentage alkali concentration for a period approximating two hours under pressure, then sizing said product and macerating the same to filll'tlflly break down the'fiber bundles, and

' en forming boards with hydrated wood paper makin pulp under pressure. 

